What are IMSI Catchers?
IMSI catchers from various manufacturers simulate a temporary mobile phone base station that attracts nearby smartphones and reads out the IMSI (International Subscriber Identity). This identity is unique worldwide and identifies the SIM card holder. This fake base station must have a better signal than the public base stations. For this reason, the IMSI catcher is only active for a few seconds.
It is therefore very important to recognize these systems in the shortest possible time.